A jabsco water puppy pump is a reversible pump. So, this means that some of the intake line is also the emptying line. Also, the jabsco acts like a check valve... from what Ive read/heard from somewhere...here i believe.

Has anyone ever plumbed a jabsco pump to empty a v-drive sac (or any other sac) through the intake thru-hull instead of drilling another hole in the boat (or plumbing into an existing emptying line), using check valves, and making a separate emptying line?

Im sure it would be slower being there would be pressure from the lake/river/reservoir/whatever. But, is the pump capable of this?

When I did a system before, I plumbed 2 pumps (for 3 bags) into the raw water intake. So when filling I took water from there, and when emptying it went back out through the entire system. The thing that I worried about was the engine overheating. At idle the engine doesn't use much water so you're usually ok, but at full power you could run into some problems.

I'll be doing another system on another boat in the next couple weeks, and if I use Jabsco/Simer pumps I'll be putting in a seperate thru-hull for them. It will just give me the peace of mind that I won't overheat.

I use a total of 6 aerator type pumps and one RV waste valve to fill and drain 3 sacks. The system has been running for a few years now, with no problems. I both fill and drain through the original motor raw water pickup which has been enlarged to a 1.5" thru hull fitting. Water is pumped backwards through the fill pumps when draining (and backwards through the drain pumps when filling), they have very little restriction when they are not on. I have never had a problem with overheating, the motors impeller type water pickup will always overpower the aeretor type pumps. There are a few hose clamps missing in this picture as I took it during the install, but you get the idea. The brass ball valve is 2" because the I.D. of the actual valve section is the same as the 1.5" pipe. Fill and drain time is about 8 minutes for all 3 proX Vdrive sacks (+/-400# ea.).

I am thinking of doing that myself, however how will you know when the sacs are completely empty and when to shut down your pump?? I know the Jabsco ballast puppy has run dry shut off protection but I don't want to have to go against the safety every time I drain. To remedy this I was planning to have 1 way check valves in the fill line near the thru hull and then t off to the drain line out the side, which would also need a 1 way check valve so it didn't suck air when you try and prime to fill.

MY initial plan was the same as yours though, have holes only in the transom and then 1 vent line for all three out the side. I don't want to have to check the sacs to make sure they are empty, so the options are time it just right, check the sacs or just run it till you think it has hit the run dry and shut off.

I am using three jabsco pumps to fill and empty thru the same hole. I do have a vent with a check valve thru the side to see when the bags are full. Correct Craft boats all come this this type of system and that is who I copied. I auctually purchased all of my thru hull fittings from my local dealer. Using the 3 Jabsco pumps with 1 inch hose I can fill 2500lbs in less than 9 minutes. I dont worry about running them too long as I just look at my watch and know how long it takes to empty.

I have no vent line, I have to manually "burp" the sacs by loosening one of the plugs and letting the air escape and then tighten back down. This picture shows one sac turned on its side, I now point the two plugs up. These pictures were taken the first day I tried it out. I am able to fill the small brick using one of the hoses from the other sacs and then move it around. Also seen in this picture is my top of tower mounted navigation light, a DIY mod of the original nav light.

These are two of the drain pumps hidden next to the back seat, the seat is removed in this picture.

And this is all the hose you see in the boat, everything is on 1" quick disconnects, so they are easy to store away under the bow when not needed. Extra gas always works as ballast also!

Again, six aerator pumps, 4 switches (one for the valve), no new holes in the boat, everything, motor included is going through a 1.5" thru hull where the original 3/4" raw water pickup was. +/- 8 minute fill/ drain times. Been working great for more than two years now. Enjoy!